1. Field of the Invention
This invention pertains to a method of and apparatus for dispensing beverage with beverage dispensing head having an electrically conductive probe that senses for dispensed beverage adjacent a lowest rim height in a tilted receptacle and when contacted by beverage in the receptacle passes an electrical signal to a dispensing control circuit that automatically terminates dispensing.
2. The Prior Art
The most relevant known prior art is L. D. McIntosh U.S. Pat. No. 3,916,963 of Nov. 4, 1975, which is owned by The Cornelius Company, assignee of the present invention. McIntosh is the original and first inventor of an automatic beverage dispensing system in which dispensing is started by the placement of a cup under a nozzle and against and into a movable conductive actuator lever, and then automatically terminated when the beverage in the cup reaches and touches the lever. The beverage reaching and touching the lever is sensed via a small electrical potential sent from the nozzle into the cup and then to the lever via the beverage in the cup. McIntosh will probably fill a cup regardless of how much ice is in it, regardless of the diameter of the cup and regardless of variation in the height of the cup.
A. M. Reichenberger U.S. Pat. No. 4,236,553 has application of a voltage potential upon the beverage in the dispensing head, and a conductive cup lever which will accomodate a range of different height cups. A sliding probe dips into the cup and below the rim to sense for beverage.
J. E. Haynes U.S. Pat. No. 3,670,765 has two probes which are inserted into the cup to control a filling level and give automatic shut-off at this level.
H. R. Karlen U.S. Pat. No. 2,639,078 has a coffee machine in which the coffee pot carries a level probe connectible to an electronic shut-off control.
D. Nickerson U.S. Pat. No. 3,839,645 has a two-level electronic fill control using either a short or tall probe inside of a beverage cup.
All of the foregoing have suffered from excessive complexity and the disclosed embodiments have not enjoyed commercial success, save for Karlen. Sanitation of the actuation lever has been a problem, as McIntosh, Reichenberger and the others all require the beverage to contact a conductive member, and insects and the like can land on these members and feed on the residual beverage. Some of the previous levers have been difficult to clean and keep sanitary. Sanitation is becoming more and more important with the re-emergence of draft beer and with the relatively new soft drinks containing high percentages of natural juices. The prior art is not sufficiently sanitary to work with 100 percent juice, high percentage juice soft drinks, or beer. Electrical shunting and feed back are also a problem because of cross-feed from adjacent valves, and because the prior art device must be washed and cleaned very carefully and then completely dried to prevent electrical malfuncions.
Push back of almost empty cups has also been a problem. The prior devices tend to push back an empty cup and then stop dispensing with an almost empty cup. The weight of an empty cup has not been enough to hold the actuator lever back, without the cup being held.
The concept of McIntosh in 1975 was very promising and was very well received, but further invention is needed to attain commercial success.